The spike has been ruled a statistical anomaly. Fatality rates have been trending down for a hundred years as beach safety practices, medical preparedness, and general awareness continue to improve. All of the reported deaths occurred outside of the U.S. in countries thought to be less developed in terms of shark safety and medical personnel and facilities.

The ISAF reviewed a total of 125 reports of "shark-human interaction" in 2011. Seventy-five of the cases were confirmed as unprovoked shark attacks on humans, down from 81 in 2010.

From the ISAF's report:

"Unprovoked attacks" are defined as incidents where an attack on a live human by a shark occurs in its natural habitat without human provocation of the shark. Incidents involving sharks and divers in public aquaria or research holding-pens, shark-inflicted scavenge damage to already dead humans (most often drowning victims), attacks on boats, and provoked incidents occurring in or out of the water are not considered unprovoked attacks.

"Provoked attacks" usually occur when a human initiates physical contact with a shark, e.g. a diver bit after grabbing a shark, a fisher bit while removing a shark from a net, attacks on spearfishers and those feeding sharks, etc.. The 50 incidents not accorded unprovoked status in 2011 included 29 provoked attacks, 13 cases of sharks biting marine vessels, one incident dismissed as not involving a shark, one air-sea disaster, three "scavenge" incidents involving post-mortem bites, and three cases in which available evidence was insufficient to determine if an unprovoked shark attack had occurred.

Should you ever be attacked by a shark, here are some safety tips courtesy of ISAF:

If one is actually under attack by a shark, we advise a proactive response. Hitting a shark on the nose, ideally with an inanimate object, usually results in the shark temporarily curtailing its attack. One should try to get out of the water at this time. If this is not possible, repeat bangs to the snout may offer temporary restraint, but the result likely become increasingly less effective. If a shark actually bites, we suggest clawing at its eyes and gills, two sensitive areas. One should not act passively if under attack - sharks respect size and power.